Offsetting press



May 19, 1959 J. B. TIEDEMANN OFFSETTING PRESS Filed Aug. 29, 1955 5 Sheets-Sheet 1 mmvm. Julius B. Tzecle'mann $11 M. Lenin? ATTORNEYS.

May 19, 1959 J. B. TIEDEMANN OFFSETTING PRESS 5 Sheets-Sheet 3 Filed Aug. 29, 1 955 INVENTOR. JuZzus B- Tiedemann ATTORNEYS.

5 Sheets-Sheet 4 ATTORNEYS.

May 19, 1959 J. B. TIEDE MANN OFFSETTING PRESS Filed Aug. 29, 1955 5 Sheets-:Sheet. 5

INVENTOR. J Julius B. Tiedemcmn BY 1 4AM Q JQJM ATTORNEYS.

OFFSETTING PRESS J. B. TIEDEMANN May 19, 1959 Flled Aug 29, 1955 United States Patent OFFSETTING PRESS Julius B. Tiedemann, Milwaukee, Wis., assiguor to A 0. Smith Corporation, Milwaukee, Wis., a corporation of New York Application August 29, 1955, Serial No. 531,054

Claims. (Cl. 153-48) This invention relates to an offsetting press for bending or offsetting sheet metal blanks in the direction of blank width.

In offsetting presses generally, a sheet metal blank is offset in the plane of its width between complementary die members carried respectively by a large heavy olfsetting head or ram and the bed of the press. Heretofore, the ram has been driven angularly to provide a vertical force component to confine the blank to be offset and a horizontal force component for offsetting the blank. 6

According to the invention, an offsetting press is pro vided with a ram which is independently driven in the vertical and horizontal directions, respectively, relative to the bed of the press to confine and offset a blank between the bed and ram.

More specifically, the offsetting press of this invention includes a frame which rests on a foundation provided for the press. The upper surface of the frame constitutes a generally rectangular working bed and carries a lower die for offsetting blanks which are fed laterally through the press. Vertical guides are provided at the ends of the frame to carry vertically moving ram support members in spaced relation. The spaced support members are adapted to move in unison within the frame guides and each support member is provided with a horizontal slide groove adjacent the upper end thereof. A press ram is disposed between the spaced support members and carries a complementary upper offsetting die in the lower face thereof for cooperation with the lower die carried by the working bed. The ram is provided with a projecting slide at each end thereof which is slidably disposed in the respective horizontal slide grooves of the support members and is adapted to be moved horizontally relative to the support members and the bed. In operation the ram is moved downwardly relative to the bed a predetermined distance by the support members to confine the blank to be offset between the ram and the bed, and then the ram is driven horizontally with respect to the bed and the support members within the slide grooves provided in the support members to offset the blank between the complementary dies carried respectively by the bed and the ram.

The drawings furnished herewith illustrate the best mode of carrying out the invention as presently contemplated and set forth hereinafter.

In the drawings:

Figure 1 is a top plan view of an offset press made in accordance with this invention showing the position of the ram at the end of the working stroke;

Fig. 2 is an end elevation of the offset press showing the drive mechanism therefor;

Fig. 3 is a side elevation of the offset press as viewed from the right in Fig. 2 showing the drive mechanism for moving the ram and ram support members in a vertical direction with respect to the bed;

Fig. 4 is a sectional view with parts broken away taken on line 4-4 of Fig. 2 showing the drive mechanism for moving the ram horizontally with respect to the bed;

Fig. 5 is an enlarged partial side elevation with parts broken away showing the drive mechanism for moving the ram support members in a vertical plane;

Fig. 6 is a partial sectional view taken on line 6--6 of Fig. 5;

Fig. 7 is an enlarged partial side elevation as viewed from the left in Fig. 2 showing the drive mechanism for feeding the blanks into the offset press;

Fig. 8 is a partial sectional view taken on line 88 of Fig. 7; and

Fig. 9 is an enlarged partial sectional view showing the die members carried respectively by the bed and ram of the offset press.

Referring to the drawings, the offset press comprises a relatively heavy frame 1 of generally rectangular shape supported on a foundation 2. The upper surface of frame 1 is substantially level and constitutes a working bed 3. The bed 3 carries the lower offsetting die 4 which cooperates with the complementary upper die 5 carried by the offset head or ram 6 adapted to move relatively to the bed 3 to offset a sheet metal blank 7 therebetween. As shown in Fig. 1 the ram 6 is generally rectangular and extends substantially the full length of bed 3 and is somewhat longer than the length of the blanks '7 to be offset.

The press is designed to offset successive blanks 7 in the direction of their width. The blanks 7 advance over the feed table 8 from the rear of the press, which is shown at the top in Figure 1, move into the press, are offset between the complementary die members in a direction counter to their advance, and pass out of the press at the front thereof, shown at the bottom of Figure 1. As each blank 7 reaches the offsetting position it is supported on a flat forwardly extending surface 4a of the lower die 4 and when the ram 6 is lowered with respect to the bed 3 a flat rearwardly extending surface 5a of the upper die 5 serves to confine the blank between the dies in the direction of the blank thickness. As the ram 6 is moved rearwardly on its working stroke, a downwardly extending surface 5b of the upper die 5 engages the forward edge of the confined blank and moves the blank rearwardly to have the rearward edge of the blank engage an upwardly extending surface 45 of the lower die 4 to offset the blank to the desired curvature between the die members. The closed die members 4 and 5 are shaped to provide an enclosure having a configuration substantially like that of the offset blank to be formed therein.

According to the invention, the ram 6 is slidably supported within a pair of movable support members 9 disposed at each end of the press. To mount the ram for sliding horizontal movement with respect to the support members 9, the ram 6 is provided at each end with an outwardly extending horizontal projection 10 which is generally coextensive with the respective ends of the ram and which is slidable within a recess 11 provided in the corresponding support members 9. Virtually no angular displacement of ram 6 relative to supports 9 is possible. Each support member 9 extends laterally substantially the full width of the press bed 3 and is slidably disposed in a vertical guideway 12 provided on the frame 1. The support members 9 are vertically actuated in unison within the guideways 12 to lower and raise the ram 6 to respectively confine and release the blank 7.

Each support member 9 is. provided with a stop 13 disposed beneath the recess 11 for engaging. the end of the bed 3 to thereby limit the downward motion of the ram to confine the blank. One or more shims 14 may be stacked on the stop engaging portion of the bed for engagement by the stop 13 so that the limit of downward movement of the ram may be set predeterminately in accordance with blank thickness.

The ram 6 and support members 9 are supported or counterbalanced by a plurality of balancing cylinders 15. A pair of cylinders rest on the foundation 2 beneath each support member 9 and are connected to the mem* ber 9 by columns 16. Fluid pressure from one or more receiver tanks, not shown, maintains a constant pressure in the balancing cylinders to support the members 9 and ram 6.

The ram 6 is independently driven in the vertical and horizontal directions, respectively. In the vertical direction the ram is carried by the support members 9 as the same move upwardly and downwardly in unison, and in the horizontal direction the ram is caused to slide in the recesses 11 provided in the movable members 9.

To actuate the movable members 9 in unison within the vertical guideways 12 provided in the frame 1 and thereby raise and lower the ram 6, a plurality of interconnected toggle mechanisms 17 and 18 are employed and operated by a single drive. Parallel shafts 19 and 20 extend longitudinally of the press and are rotatably supported by the frame 1 in a horizontal position to form a fixed pivot for the respective toggle mechanisms 17 and 18. The ends of shafts 19 and 20 extend through vertically elongated openings 21 provided in the respective support members 9 to permit vertical movement of the members with respect to the shafts.

The toggle mechanisms 17 each comprise upper toggle links 22 which are fixedly secured to the ends of shaft 19 outwardly of support members 9. The corresponding lower toggle links 23 are pivotally mounted on the sup port members 9. A center pivot shaft 24 pivotally joins the upper toggle links 22 to the corresponding lower toggle links 23 thereby connecting the shaft 19 to the respective movable members 9.

For each toggle mechanism 17 on shaft 19 there is a corresponding toggle mechanism 18 on shaft 20 with the corresponding toggle mechanism being longitudinally I aligned. The toggle mechanisms 18 are similar to the toggles 17 and include the upper toggle link 25 fixedly secured to the shaft 20 adjacent the end thereof out wardly of the respective support members 9. The lower toggle links 26 are pivotally joined to the support members 9. Center pivot shafts 27 pivotally connect therespective links 25 to their corresponding lower toggle links 26.

The connecting rod 28 joins the center pivot shafts 24 and 27 of each set of corresponding toggle mechanisms 17 and 18 to assure simultaneous operation of the mechanisms to raise and lower the respective support members 9 and arm 6.

A lever 29 is fixedly secured on shaft 19 to rotate the shaft and thereby open and close the respective toggle mechanisms to raise and lower the ram. Referring to Figs. 3 and 5 of the drawings, counter-clockwise rotation of shaft 19 opens the toggle mechanisms 17 and 18 and raises the support members 9 to carry the ram 6 upwardly. Clockwise rotation of shaft 19 closes the toggle mechanisms 17 and 18 moving the support members 9 and the ram carried thereby downwardly until the stops 13 on the support members engage the bed 3 or the shims 14 disposed on the stop engaging portion of the bed. As will be more fully explained hereinafter, the toggle mechanisms are preferably not permitted to reach their dead center position in the fully closed position.

The drive for operating the ram independently in the vertical and horizontal directions includes a transversely extending driven shaft 30 which is rotatably mounted to the frame 1 and driven through suitable gearing by motor 31. Brake and clutch mechanisms, shown gen erally in Fig. 2 adjacent to motor 31 are provided in the drive to control the operation of shaft 30. As best shown in Figs. 2 and 4, shaft 30 carries a pair of spaced identical sized pinion gears 32 and .33. which-serve to drive the identical sized bull gears 34 and 35 respectively to rotate the aligned bull gear shafts 36 and 37 rotatably mounted on the frame 1 in parallel relation with shaft 30. With identical sized pinion and bull gears interposed between shaft 30 and bull gear shafts 36 and 37, shafts 36 and 37 rotate together at the same speed.

A pair of cams 38 and 39 are rotatably carried by the bull gear shaft 37 to actuate a rocker arm 40 about its pivot shaft 41 which is rotatably mounted on the frame 1. A bifurcated projection 42 extends downwardly from the rocker arm 40 and oscillates therewith. A bellcrank 43 having its central pivot 44 pivotally mounted to the rocker arm 40 is normally maintained in substantially fixed relation to the rocker arm by means of a safety mechanism 45 disposed between one end of the bellcrank 43 and the bifurcated projection 42 on the rocker arm. The bellcrank 43 therefore normally oscillates with the rocker arm 40 in accordance with rotation of cams 38 and 39 on shaft 37. A connecting link 46 is pivotally connected at one end to lever 29 on shaft 19 and has the other end thereof pivotally connected at 47 to the bellcrank 43 so that shaft 19 oscillates in accordance with oscillation of the rocker arm 40. Thus, rotation of shaft 30 by the motor 31 oscillates the rocker arm 40 and the bellcrank 43 is normally maintained in generally fixed relation to the rocker arm to actuate lever 29 and thereby rotate shaft 19 to close and open the toggle mechanisms 17 and 18 to lower and raise the ram 6.

The safety mechanism 45 is interposed in the ram lift drive to protect the drive mechanism in the event the ram 6 is somehow prevented from reaching its fully lowered position, as when a pair of blanks 7 are erroneously fed into the press in stacked relation. Safety mechanism 45 is comprised of a cylinder 48 pivotally carried by the bifurcated projection 42 on the rocker arm 40. A piston 49 having a rod 50 is disposed in the cylinder 48 and normally fluid pressure from a source, not shown, acts on the piston to maintain the same in abutting relation with one end of the cylinder. The rod 50 extends through the opposite end of cylinder 48 and is provided with threads 51 outwardly of the cylinder. A trunnion member 52 is adjustably mounted on the threaded portion of the piston rod 50 and is pivotally supported at one end of the bellcrank 43. The lock nuts 53 and 54 secure the trunnion member 52 with respect to the piston rod 50. As long as the pressure acting on piston 49 within cylinder 48 exceeds the force required to rotate shaft 19 to close the toggle mechanisms the rocker arm 40 and bellcrank 43 will oscillate as substantially an integral unit. When the forces set up in the ram lift drive exceed the cylinder pressure, the positively driven rocker arm 40 continues to oscillate while the bellcrank 43 pivots with respect to the rocker arm pulling the piston 49 against the cylinder pressure to cushion the load and thereby prevent breakage of any elements of the drive mechanism.

In operation, the ram height in the offset or down position is dependent on the blank thickness. Shims 14 are interposed between the support members 9 and the bed 3 to set the ram 6 at the correct offsetting position for a given blank thickness. The amount of rotation of lever 29 on shaft 19 and the degree of closure of toggle mechanisms 17 and 18 will vary in accordance with the ram height setting. The oscillations of the positively driven rocker arm 40, however, remain the same regardless of the ram height setting. Thus, to reconcile the positive operation of the rocker arm 40 and the variable operation of the toggle mechanisms 17 and 18, the trunnion member 52 on rod 50 is set so that there will be a small amount of relative movement between the rocker arm 40 and bellcrank 43 and the piston 49 will be pulled slightly from its end abutting position in the cylinder 48 against the fluid pressure therein when the ram height setting is for a blank of minimum thickness. As the ram height setting is modified to accommodate blanks of greater thickness and toggle mechanisms 17 and 18 close to a lesser degree, more relative movement between the rocker arm 40 and the bellcrank 43 takes place and the piston 49 is pulled further from its end abutting relation in cylinder 48 to cushion the drive mechanism.

It should be noted that toggle mechanisms 17 and 18 should preferably not close to the extent of placing their respective center pivot shafts 2- 5 and 27 in the dead center position of the toggles. For a ram height setting to accommodate a blank of minimum thickness the center pivot shafts 24 and 27 should be slightly offset from the dead center position of the toggles. This nearly straight position of the toggles is sufficient to permit substantial resistance to any tendency of support members 9 to be raised from their lowered position during the offsetting stroke. Members 9, and thus ram 6, are substantially secured in position by the vertical holding force imposed by the toggles.

The ram 6 is independently motivated horizontally within the recesses 11 in the support members 9 to offset the blank 7. To effect horizontal movement of the ram 6, a pair of oscillating members 55 are pivotally mounted to the frame 1 and extend upwardly therefrom. Connecting links 56 have one end thereof pivotally secured to the upper end of the respective oscillating members 55 and the other ends thereof pivotally secured to the ram whereupon oscillation of the members 55 causes the ram 6 to reciprocate within the recesses 11 of movable members 9.

The oscillating members 55 are each driven by a crank member 57 which has one end pivotally mounted to each member 55 between the frame pivot and connecting link pivot of the members. The opposite end of each crank member 57 is disposed about a corresponding offset circular cam 58, one of which is carried by each bull gear shaft 36 and 37. The circular earns 58 are offset in a similar manner on the respective shafts 36 and 37 so that rotation of the shafts at the same speed results in members 55 oscillating together to reciprocate the ram 6 horizontally in the recesses ll of support members 9.

The angular relation between the offset cams 58 on the shafts 36 and 37' and the ram lift cams 38 and 39 on shaft 37 is such that the ram travel pattern for one complete cycle describes a parallelogram. Upon rotation of shafts 36 and 37, the lift cams 36 and 39 lower the ram to confine the blank between the ram and the bed. While the ram moves downwardly, the offset earns 58 have begun to move the ram horizontally to begin the offsetting stroke. Upon closure of the die members 4 and 5 carried by the bed and ram, respectively, the ram continues in a horizontal direction to offset the blank between the die members. At the end of the offsetting stroke the lift cams proceed to raise the ram while at the same time the offset cams start the ram on its return stroke. After the ram has reached its uppermost open position, the ram continues its horizontal return stroke to its original position completing the travel pattern describing a parallelogram.

The blanks i are advanced laterally in intermittent stages over the feed table 8 in a direction counter to the offsetting stroke of the ram and in timed sequence with the rain so that a single blank arrives at the offsetting position each time the ram begins an offsetting stroke in the ram cycle. After the blank has been offset it continues to advance over the work table in intermittent stages to a location, not shown, where the offset blanks are stacked in preparation for further processing.

A preferred mechanism for laterally advancing the blanks 7 in intermittent stages through the press includes a plurality of generally parallel spaced reciprocating feed bars 59 disposed in guides 66 supported by the frame 1. Each feed bar 59 carries a plurality of spaced spring biased dogs 61 which are aligned with corresponding dogs on all other feed bars. Thus, as feed bars 59 reciprocate together in the direction of blank advance, correspondingly aligned dogs 61 move a single blank over a distance corresponding to the reciprocation of the feed bars. As the feed bars reciprocate together rearwardly, the spring biased dogs 61 are depressed below the next succeeding blank, and upon clearing the rearward edge of the blank raise up in preparation for moving that blank on the next reciprocation.

A plurality of depressible stop dogs 62 project upwardly from the bed 3 forwardly of the offset position in the direction of blank advance. The stop dogs 62 are in the raised position as each blank approaches the offset position to assure proper alignment of the blank with respect to the offsetting dies preparatory to the offsetting stroke of the ram. The stop dogs 62 are depressed during the offsetting stroke of the ram and remain depressed until the newly offset blank clears the stop dogs. After the newly offset blank has cleared the stop dogs 62 they are raised up to provide stop means for the next succeeding blank entering the offsetting position.

An actuating means for stop dogs 62 is shown schematically in Fig. 4, and comprises a vertical lever-arm 62a pivotally secured at its top end to the left end of dog 62. The bottom end of lever 62a is pivotally connected to one end of a horizontal link 6211 which is centrally mounted on a fixed pivot 62c. The other end of link 62b is pivotally connected to a contact member 62d which extends upwardly into engagement with the underside of ram 6. As the ram comes down, it actuates contact member 62d to pivot link 62b and arm 62a to lower dog 62 out of the way of the blank 7. After the blank has cleared the offsetting area and ram 6 moves upwardly, the lever mechanism will raise dog 62, either due to the unbalancing weight of arm 62a or by spring biasing means, not shown.

Theindividual feed bars 59 are simultaneously reciprocated to advance the blanks 7 by corresponding connecting links 63 having one end thereof pivotally secured to the respective feed bars. The other ends of connecting links 63 are pivotally secured to the upper ends of corresponding oscillating arms 64 and translate the oscillating motion of arms 64 to the reciprocating motion of the feed bars. The lower ends of arms 64 are fixedly mounted to a shaft 65 rotatably mounted on the frame land oscillate therewith.

The shaft 65 takes its oscillating motion from a shaft 66 which is mounted on the frame in parallel relation to shaft 65. Levers 67 and 68 are fixedly secured on the respective shafts 65 and 66 and are pivotally connected by link 69 to transmit the oscillations of shaft 66 to shaft 65.

The shaft 66 is driven by a rocker arm 70 which is fixedly mounted on shaft 66 and imparts its oscillating motion to the shaft to reciprocate the feed bars 59 and thereby advance the blanks '7. Cams 71 and 72 carried by the bull gear shaft 36 drive the rocker arm 70 to reciprocate the feed bars 59 in timed relation with the ram cycle so that a blank 7 arrives at the offsetting position prior to the offsetting stroke of the ram.

The invention provides an offsetting press wherein the drive is located below the working surface of the bed. The massive super structure of conventional presses for supporting the drive above the bed is therefore eliminated resulting in substantial cost reduction. The invention further provides a press wherein the head and head die may be preset for a given offset clearance in accordance with blank thickness. Canting or buckling of the ram is substantially prevented by the linkage which is operative at the four corners of the ram and outside the confines of the die area.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In an offsetting press for bending sheet metal blanks in the direction of blank width and with said press having a fixed frame, a generally rectangular bed disposed on said frame having a substantially horizontal working surface, a die member disposed in the working surface of said bed, means for feeding a blank in the direction of blank width onto the bed die member, an offsetting head disposed above the working surface of the bed and carrying a complementary die member and being adapted to move in parallel relation to the bed to oifset the blank between the complementary die members, and means connected between said frame and said head and operative at the four corners of said head and outside the confines of the die area to impose a vertical holding force on said head during offsetting to confine the head against angular movement with respect to the bed during offsetting and to impose a substantially constant clamping pressure on the blank.

2. In an ofisetting press for bending sheet metal blanks in the direction of blank Width, a frame, a first die member for bending the blanks and carried by the frame, feeding means for advancing successive blanks forwardly in the direction of their width onto the first die member, a second die member disposed above the first die member, a support member disposed at each end of the frame and mounted for movement vertically with respect to the first die member and carrying the second die member, linkage means to simultaneously actuate the support members vertically to clamp successive blanks between the complementary die members, said linkage means being operative at the four corners of said frame and outside the confines of the die area to substantially hold said support member against vertical movement at the lower end of their stroke, and horizontally extending guide means provided in the support members and wherein the second die member is substantially confined against angular movement and is slidably moved in parallel relation with the first die member to bend successive blanks after the same have been clamped between the die members.

3. In an offsetting press for bending sheet metal blanks in the direction of blank Width, a bed, a die member for bending the blanks and carried by the bed, means for feeding a sheet metal blank in the direction of blank width onto the bed die member, vertical guide means provided at opposed ends of the bed, a support member disposed for vertical movement in each of the guide means, a head carrying a complementary die member disposed above the bed and extending between said support members, horizontally extending guide means provided in each of said support members for slidably receiving the head, linkage means to simultaneously actuate the support members vertically within the vertical guide means to move the head relative to the bed to clamp the blank between the complementary die members, said linkage means being operative at the four corners of the frame and outside the confines of the die area to substantially hold said support member against vertical movement at the lower end of their stroke, and means to move the head relative to the support members and to the bed to bend the blank in a direction counter to the direction of blank feed after the same has been clamped between the complementary die members.

4. In an offsetting press for bending sheet metal blanks in the direction of blank width, a frame, a generally rectangular bed disposed on said frame and having a substantially horizontal working surface, a die member for bending the blanks disposed in the working surface of the bed, means for feeding a sheet metal blank in the direction of blank width and laterally of the bed onto the bed die member, an offsetting head disposed above the working surface of the bed and carrying a complementary die member, a longitudinal projection provided on each end of the head and extending laterally of the head, a support member disposed at each end of the bed and having a laterally extending groove for slidably receiving the longitudinal projections on the head to support the head and head die member, linkage means disposed between said frame and said support member and operative at the four corners of said head and outside the confines of the die area to actuate the support members simultaneously in a vertical direction with respect to the bed to clamp the blank between the complementary die members, said last-named means providing a vertically acting holding force on said support members during offsetting, and drive means to move the head laterally within the grooves of said movable members to bend the blank after the same has been clamped between the complementary die members.

5. In an offsetting press for bending sheet metal blanks in the direction of blank width, a bed having a substantially horizontal working surface, a die member disposed in the working surface of the bed, means for feeding a blank in the direction of blank width and laterally of the bed onto the bed die member, an ofisetting head disposed above the working surface of the bed and carrying a complementary die member, an outwardly extending projection provided on each end of the head, vertically extending slides provided on each end of the bed, a support member disposed at each end of the bed and disposed to move vertically within said slides and having a horizontally extending groove therein for slidably receiving the projections on the head to support the head and head die member, means operative at the four corners of said head and outside the confines of the die area to actuate the support members simultaneously within the vertically extending slides to clamp the blank between the complementary die members and to hold said support members against vertical movement at the lower end of their stroke, and drive means to move the head within the grooves of said support members to bend the blank after the same has been clamped between the complementary die members.

6. In an offsetting press for bending sheet metal blanks in the direction of blank width, a generally rectangular bed having a substantially horizontal working surface, a die member disposed in the working surface of the bed, means for feeding a blank in the direction of blank width and laterally with respect to the bed onto the bed die member, an oifsetting head disposed above the working surface of the bed and carrying a complementary die member, an outwardly extending projection provided on each end of the head and extending laterally of the head, a support member disposed at each end of the bed for movement vertically with respect to the bed and having a horizontally extending groove therein adjacent the upper end thereof to slidably receive the projections on said head, a stop surface provided on the support member beneath the groove therein, adjustment means disposed on the working surface of the bed beneath the stop surfaces of the support members for engagement by said stop surfaces, means to actuate the support members downwardly simultaneously to set the stop surfaces of the movable members down onto the adjustment means and thereby clamp the blank between the complementary die members with the adjustment means establishing the offsetting clearance between the die members in accordance to the thickness of the blank, and drive means to move the head horizontally within the grooves of said support members to bend the blank after the same has been clamped between the complementary die members.

7. In an offsetting press for bending sheet metal blanks in the direction of blank width, a bed, a die member for bending the blank and carried by the bed, means for feeding a sheet metal blank in the direction of blank width onto the bed die member, a support member disposed at each end of the bed and mounted for movement vertically with respect to the bed, a head carrying a complementary die member disposed above the bed and mounted to the support members for movement relative thereto and in parallel relation to the bed, toggle means operative at the four corners of said head and outside the confines of the die area to actuate the support members vertically simultaneously to clamp the blank between the complementary die members and to hold said support members against vertical movement at the lower end of their stroke, and means to move the head and head die member relativeto the support members and to the bed to bend the blank after the same has been clamped between the complementary die members.

8. In an offsetting press for bending sheet metal blanks in the direction of blank width, a frame having a substantially horizontal generally rectangular working bed, a die member for bending the blanks disposed in the working bed, means for feeding a sheet metal blank in the direction of blank width and laterally of the bed onto the bed die member, an offsetting head disposed above the bed and carrying a complementary die member, a guide member provided on each end of the head, a movable ram support member mounted on the frame and disposed at each end of the bed and having a generally horizontal groove for slidably receiving the guide member on the head to support the head and the head die member, a plurality of toggle mechanisms supported by the frame and disposed between the frame and the movable ram support members, means to simultaneously actuate the toggle mechanisms to a closed position to move the support members and head downwardly with respect to the bed to clamp the blank between the complementary die members, and drive means to move the head with respect to the bed within the grooves of said support members to bend the blank after the same has been clamped between the complementary die members.

9. In an offsetting press for bending sheet metal blanks in the direction of blank width, a foundation, a frame disposed on the foundation and having a substantially horizontal working bed, a longitudinally extending die member for bending the blanks disposed in the working bed, means for feeding a sheet metal blank in the direction of blank width and onto the bed die member, an offsetting head supported by the frame and disposed above the bed and carrying a complementary die mem her, a flange provided on each end of the head, vertically extending slides provided on the frame at the ends of the bed, a support member disposed at each end of the bed and adapted to move vertically within said slides and having a horizontally extending groove for slidably receiving the flanges on the head to support the head and head die member, a plurality of balancing cylinders supported by the foundation and connected to the support members for supporting the movable members and head to counterbalance the weight thereof, a plurality of toggle mechanisms supported on the frame disposed between the frame and the support members, means to simultaneously actuate the toggle mechanisms to a closed position to move the support members and head downwardly against the pressure in said cylinders to clamp the blank between the complementary die members, and drive means to move the head generally parallel with respect to the bed within the grooves of said support members to bend the blank after the same has been clamped between the complementary die members.

10. In an offsetting press for bending sheet metal blanks in the direction of blank width, a frame having a substantially rectangular horizontal working bed, a die member for bending the blanks disposed in the working bed, means for feeding a sheet metal blank in the direction of blank width and laterally of the bed onto the bed die member, an offsetting head disposed above the bed and carrying a complementary die member, a flange provided on each end of the head, vertically extending slides provided on the frame at the ends of the bed, a support member disposed at each end of the bed and adapted to move vertically Within said slides and having a generally horizontal groove for slidably receiving the flanges on the head to support the head and head die member, a counterbalancing means supporting the support members and head, a plurality of toggle mechanisms mounted on the frame and disposed between the frame and the support members, said toggle mechanisms being interconnected to be operated in unison to lower the support members against the counterbalancing means and providing substantial resistance against vertical movement of the support members when the latter are at the lower end of their stroke, said head and head die member moving downwardly with the support members to clamp the blank between the complementary die members, a rocker arm pivotally connected to the frame to actuate one of said toggle mechanisms to a closed position and thereby effect closure of the interconnected toggle mechanisms, means to actuate the rocker arm, a safety mechanism disposed between the toggle mechanism actuated by the rocker arm and the rocker arm to permit continued operation for the rocker arm when an obstruction between the die members prevents closure of the toggle mechanisms, and drive means to move the head laterally with respect to the bed within the grooves of said support members to bend the blank. after the same has been clamped between the complementary die members.

References Cited in the tile of this patent UNTTED STATES PATENTS 1,340,138 Miller May 11, 1920 1,466,104 Smith et al Aug. 28, 1923 1,921,210 Ziska Aug. 8, 1933 

